Recombination in recA cells between direct repeats of insertion element IS1

Braedt, Gary

doi:10.1128/jb.162.2.529-534.1985

Cited by 8 publications

(1 citation statement)

References 34 publications

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“…The analysis of the JE2571Rif r transconjugants surviving pAZAKT transfer showed that it was not due to the development of Zeta resistance. The survivors contained either an inactivated zeta gene or a recombinant of pAZAKT and the Epsilon-encoding plasmid from the donor, most probably due to the activity of chromosomally carried IS 1 ( 41 ).…”

Section: Discussionmentioning

confidence: 99%

A Novel Mobilizing Tool Based on the Conjugative Transfer System of the IncM Plasmid pCTX-M3

Dmowski

Kern-Zdanowicz

2020

Appl Environ Microbiol

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Conjugative plasmids are the main players in horizontal gene transfer in Gram-negative bacteria. DNA transfer tools constructed on the basis of such plasmids enable gene manipulation even in strains of clinical or environmental origin, which are often difficult to work with. The conjugation system of the IncM plasmid pCTX-M3 isolated from a clinical strain of Citrobacter freundii has been shown to enable efficient mobilization of oriTpCTX-M3-bearing plasmids into a broad range of hosts comprising Alpha-, Beta-, and Gammaproteobacteria. We constructed a helper plasmid pMOBS mediating such mobilization with an efficiency up to 1000-fold higher than that achieved with native pCTX-M3. We also constructed E. coli donor strains with chromosome-integrated conjugative transfer genes: S14 and S15, devoid of one putative regulator (orf35), and S25 and S26, devoid of two putative regulators (orf35 and orf36) of the pCTX-M3 tra genes. Strains S14 and S15, and S25 and S26 are, respectively, up to 100 and 1000 times more efficient in mobilization than pCTX-M3. Moreover, they also enable plasmid mobilization to the Gram-positive bacteria Bacillus subtilis and Lactococcus lactis. Additionally, the constructed E. coli strains carried no antibiotic resistance genes that are present in pCTX-M3 to facilitate manipulations with antibiotic-resistant recipient strains, such as those of clinical origin. To demonstrate possible application of the constructed tool, an antibacterial conjugation-based system was designed. Strain S26 was used for introduction of a mobilizable plasmid coding for a toxin, resulting in the elimination of over 90% of recipient E. coli cells. IMPORTANCE The conjugation of donor and recipient bacterial cells resulting in conjugative transfer of mobilizable plasmids is the preferred method enabling the introduction of DNA into strains for which other transfer methods are difficult to establish (e.g., clinical strains). We have constructed E. coli strains carrying the conjugation system of the IncM plasmid pCTX-M3 integrated into the chromosome. To increase the mobilization efficiency up to 1000-fold, two putative regulators of this system, orf35 and/or orf36, were disabled. The constructed strains broaden the repertoire of tools for the introduction of DNA into the Gram-negative Alpha-, Beta-, and Gammaproteobacteria, as well as into Gram-positive bacteria such as Bacillus subtilis and Lactococcus lactis. The antibacterial procedure based on conjugation with the use of the orf35- and orf36-deficient strain lowered the recipient cell number by over 90% owing to the mobilizable plasmid-encoded toxin.

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Section: Discussionmentioning

confidence: 99%

A Novel Mobilizing Tool Based on the Conjugative Transfer System of the IncM Plasmid pCTX-M3

Dmowski

Kern-Zdanowicz

2020

Appl Environ Microbiol

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Helix–Coil transition of plasmid dna by adiabatic differential scanning microcalorimetry

Maeda¹,

Takahashi

Yamaki³

et al. 1988

Biopolymers

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SynopsisAdiabatic differential scanning microcalorimetry, which provides curves of the heat capacity vs temperature, was carried out for the DNA of plasmid pJL3-TB5 (5277 base pairs in length). The calorimetry curve shows nine peaks ranging from 81 to 96°C in 1 X SSC buffer at a heating rate of 0.25'C, due to the stepwise helix-coil transition of the DNA along the molecular chain. The theoretical melting curve, which can be constructed by calculation from the entire nucleotide sequence of the plasmid DNA by the helix-coil transition theory, is then compared with the calorimetry curve. The two curves resemble each other remarkably well, particularly when a parameter for the methylated adenine residues at GATC sites by Dam methylase is used appropriately. This allows us to assign each peak in the calorimetry curve to the melting of the respective regions of the plasmid DNA sequence. The local stability of the helix-coil transition along the DNA chain is closely related to the functional regions coded by pJL3-TB5, such as genes, transcriptional promoters, and particular sites generated by recombination of two different sequences in vivo and in vitro.

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IS1-mediated mobility of the aerobactin system of pColV-K30 in Escherichia coli

Herrero

Neilands

1988

Mol Gen Genet

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Genes determining the high affinity iron transport system mediated by the siderophore aerobactin are flanked in the enterobacterial plasmid pColV-K30 by inverted repeats of IS1 sequences, suggesting that the aerobactin genes are part of a transposon. To study this possibility, the entire region between the two IS1 sequences was cloned as an 18 kb HindIII-BamHI restriction fragment in pUC8 giving plasmid pMO1. A number of derivatives of pMO1, in which aerobactin genes were tagged with a kanamycin resistance gene, were prepared in order to assess the ability of both IS1s to promote the formation of cointegrates with pCJ105, an F derivative devoid of insertion sequences. Mating-out assays indicated that both flanking IS1s were active in cointegrate formation at detectable frequencies. In some cases,the cointegrates could be resolved, the final result being a transposition-like event for the entire aerobactin system.

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Recombination in recA cells between direct repeats of insertion element IS1

Cited by 8 publications

References 34 publications

A Novel Mobilizing Tool Based on the Conjugative Transfer System of the IncM Plasmid pCTX-M3

A Novel Mobilizing Tool Based on the Conjugative Transfer System of the IncM Plasmid pCTX-M3

Helix–Coil transition of plasmid dna by adiabatic differential scanning microcalorimetry

IS1-mediated mobility of the aerobactin system of pColV-K30 in Escherichia coli

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